NASHVILLE, Tenn. (AP) _ Another Columbia/HCA Healthcare Corp. executive is leaving, the 12th senior executive to exit the troubled company this year.

David Manning, who is leaving start a health care consulting business, has for three years served as Columbia's senior vice president in charge of government relations and issues concerning Medicaid and the uninsured, the company said this week.

The company is the target of a sweeping federal investigation into whether Columbia/HCA overbilled government health care programs.

As Tennessee's finance commissioner before joining Columbia, Manning helped craft the TennCare plan that provides health care to needy state residents.